(a) Field of the Invention
The present invention relates to a structure of a bubble prevention buffer tank of a fuel cell vehicle for reducing generation of air bubbles in a buffer tank.
(b) Description of the Related Art
Generally, the stack operating temperature a fuel cell system is 60° C. to 70° C. Thus, a great amount of coolant and a radiator having a great heat radiating capacity are needed. When a great amount of coolant flows into a buffer tank in a coolant circulation loop, surrounding air is sucked into a coolant tank, and this deteriorates cooling capacity and causes cavitation phenomenon in the pump so as to damage the pump.
In order to dissipate reaction heat, the stack must be cooled by a coolant. The most common coolant for a fuel cell stack is DI-water which humidifies the stack. In such case where a coolant directly humidifies the inner part of stack, water balance is required to be suitably adjusted for humidifying. To ensure to provide water balance in the stack, decreasing or increasing the total amount of flow of coolant must be possible. In order to meet this requirement, a buffer tank must be provided in a cooling loop.
Since great amount of coolant inflows to or outflows from the buffer tank while one side of the buffer tank is exposed to atmospheric pressure, air bubbles on the surface of coolant may be sucked and the bubbles may circulate in a cooling loop. The bubbles circulating in the cooling loop may damage blades of the coolant pump and may cause noises.
There is thus a need for a structure of a bubble prevention buffer tank that can reduce generation of air bubbles in a buffer tank so as to prevent malfunction of a coolant pump and to stably maintain the performance of a stack.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.